Collector panels designed for solar energy heating systems in conventional installations traditionally require heavy facing panes of glass, preferably safety glass to resist the impact of hailstones and to carry snow and ice loads, combined with sheet metal structural enclosures forming flat boxes designed to be mounted on slanted roof tops or supported on slanted frames exposed to solar radiation. Major glass manufacturers have offered these conventional solar panels for sale at prices which have been high enough to place solar energy heating systems beyond the reach of a large proportion of the population.